US3742295A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lighting system in copying apparatus
Assignee: Minolta Co Ltd
•
Filing: 1971-03-17
•
Granted: 1973-06-26
•
Expires: 1991-03-17
Abstract
Abstract A lighting system comprises a triac included in the electric circuit of an exposure lamp in series therewith and a trigger circuit for triggering the triac into conduction at a small conduction angle simultaneously when a main switch is turned on and triggering the triac into conduction at a large conduction angle simultaneously when a start switch is turned on. The system protects the contacts and other switching elements of switches from possible damage to be caused when the exposure lamp is turned on and permits a short period of exposures.
Inventors
- 👤 Y Irie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:09
CPC Classifications
H; H05; H05B; H05B39/00; H05B39/02; H05B41/00; H05B41/14; H05B41/30; H05B41/32
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
152 words
A lighting system in a copying apparatus including a main switch for actuating said apparatus, means including a start switch responsive to the advance of a sheet for initiating a copying cycle, a light source, and means including a triac in series with said light source for connecting said light source to a source of current and having a triggering electrode, further comprising a first trigger circuit means responsive to the actuation of said main switch for applying a preset constant small conduction angle signal to said triac trigger electrode concurrently with the actuation of said main switch to partially energize said light source, and second trigger circuit means responsive to the actuation of said start switch for applying a preset constant large conduction angle signal to said triac trigger electrode to increase the current through said light source to full illumination energization, following the triggering by said first trigger circuit means.
Claim 2
Dependent Claim
152 words
A lighting system in a copying apparatus including a main switch for actuating said apparatus, means including a start switch responsive to the advance of a sheet for initiating a copying cycle, a light source, and means including a triac in series with said light source for connecting said light source to a source of current and having a triggering electrode, further comprising a first trigger circuit means responsive to the actuation of said main switch for applying a preset constant small conduction angle signal to said triac trigger electrode concurrently with the actuation of said main switch to partially energize said light source, and second trigger circuit means responsive to the actuation of said start switch for applying a preset constant large conduction angle signal to said triac trigger electrode to increase the current through said light source to full illumination energization, following the triggering by said first trigger circuit means.
Claim 3
Dependent Claim
73 words
The lighting system as set forth in claim 1 wherein said trigger circuit means includes an oscillator provided with a terminal for triggering said triac into a conducting state at a small conduction angle simultaneously when said main switch is turned on and another terminal to be incorporated into said circuit by the operation of said start switch so as to trigger said triac into a conducting state at a large conduction angle.
Claim 4
Dependent Claim
68 words
The lighting system of claim 1 wherein said first trigger circuit means includes a diac, a resistor and a capacitor and triggers said triac through said diac which is connected in series between said resistor and capacitor into a conduction state at a small conduction angle in accordance with a time constant which is a function of said resistor and capacitor upon the closing of said main switch.
Claim 5
Dependent Claim
19 words
The lighting system of claim 1 comprising means including a variable resistor for adjusting said small conduction angle signal.
Claim 6
Dependent Claim
29 words
The lighting system of claim 1 wherein said first trigger circuit means for maintaining the conduction angle of said triac is independent of voltage changes in said current source.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |